Digital Phase Measurement Using Zero-Crossing and Fraction Averaging
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Solution Overview
Problem
Existing phase measuring devices face limitations in measuring phase or phase differences of periodical input signals with wide frequency ranges and varying frequencies, often resulting in reduced accuracy, resolution, and real-time processing capabilities due to complex circuit configurations and noise instability.
Innovation Solution
A digital phase measuring device that combines counting and zero-crossing methods, using A/D converters to digitize input signals, zero-crossing identification, counting processing units, fraction processing, and averaging processing to calculate phases or phase differences at equal time intervals, enabling high accuracy and real-time processing across a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional phase measuring devices use complex circuit configurations to improve measurement accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex analog phase measurement circuits with a digital processing system. An A/D converter converts the analog input signal to digital data, which is then processed by a CPU using algorithms (such as zero-crossing detection, correlation methods, or Fourier transform) to calculate phase. This substitution of mechanical/analog systems with digital ones simplifies the hardware architecture while maintaining or improving measurement accuracy through software-based signal processing.
2Productivity
If phase measuring devices use high sampling rates to improve real-time processing capability, then processing speed is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements adaptive sampling strategies where the sampling rate is adjusted based on the actual measurement requirements and signal characteristics. Rather than continuously operating at maximum sampling rates, the system uses lower sampling rates when sufficient accuracy can be achieved, and only increases sampling rates when real-time performance demands it. This partial application of high sampling capability reduces overall system complexity and resource consumption while maintaining real-time processing capability when needed.
3Adaptability or versatility
If phase measuring devices are designed for wide frequency range to improve adaptability, then adaptability is improved, but measurement precision deteriorates
Solution Approach 1:
The patent employs dynamic parameter adjustment mechanisms that adapt the measurement system's characteristics based on the input signal frequency. The CPU analyzes the frequency of the input signal and dynamically adjusts sampling rates, filter parameters, and processing algorithms to optimize performance for each frequency range. This dynamic adaptation allows the system to maintain high measurement precision across a wide frequency spectrum by continuously optimizing its operating parameters rather than being fixed to a single configuration.
4Ease of operation
If conventional devices use analog circuits for phase measurement, then ease of operation is maintained, but reliability deteriorates due to noise instability
Solution Approach 1:
The patent replaces noise-sensitive analog phase measurement circuits with a digital processing system. The A/D converter transforms the analog signal into digital data, which is then processed using digital signal processing techniques such as correlation analysis, zero-crossing detection, or spectral methods. These digital methods are inherently more immune to noise and instability issues that plague analog circuits, while the system remains easy to operate through automated algorithms that require minimal user intervention for parameter adjustment.
Data Source
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AI summary
The inventive phase measuring device includes a first A/D converter 2 that digitizes a first periodical input signal X at each predetermined sampling timing and outputs the resultant signal as a digital signal Xd, a first zero-crossing identification means operable to detect a sign of Xd, a counting processing unit 4 that counts a difference in the number of times of zero-crossing detection by the first zero-crossing identification means and calculates the difference at each sampling timing, and a fraction processing unit 5 that computes a fraction of the number of times of zero-crossing detection on the basis of Xd at sampling timings immediately before and immediately after determination of zero-crossing by the first zero-crossing identification means. An averaging processing unit 6 performs averaging by adding up and totalizing the outputs from the counting processing unit 4 and the fraction processing unit 5, thereby computing a phase. The inventive device thus implements a digital phase measuring device and a digital phase difference measuring device that allow input of periodical signals in a wide frequency range and that are capable of accurate and real-time measurement.